No idea if this belongs here, but if it's in the wrong place I'm sure someone will be kind enough to move it ^_^

Flicking through some past exam papers I've stumbled across a question I can't see how to even begin answering, it's nested in with some other parts of the question so I can't determine exactly how many marks it's worth to gauge an expected length for the answer, but anyhow, the question asks:

Derive a relationship between the convergence speed and the spectral radius for the method of Gauss-Seidel in solving the system of linear equations,
Ax = b